The field of the invention generally pertains to container closures. The invention relates more particularly to container closures having a dispensing cap and a cover captively movable between a closed position over the dispensing cap and an open position remotely spaced from the dispensing cap by means of a resiliently-biasing web-hinge structure.
Various types of container closures having dispensing caps with hinged captive covers have been utilized in the packaging industry for many years. They have typically been used to package personal care and household chemical products such as shampoos, lotions, cleaning fluids, etc. Many of these container closures utilize a resiliently biasing hinge structure to connect the captive cover to the dispensing cap. The hinge structure has a snap-action biasing force which maintains the captive cover in a desired open or closed bistable position. This is useful to prevent the captive cover from blocking or otherwise interfering in the dispensation and use of the contents contained therein.
For example, in U.S. Pat. No. 4,403,712 an integral snap hinge is shown connecting the body of a bottle closure to a lid. The integral snap hinge directly connects the body and the lid by means of a single, geometric main film hinge and two connecting elements located at each end of the main film hinge. Each connecting element is linked to the body and the lid also by film hinges which merge with the single, geometric main film hinge. The connecting elements and the walls of the hinge members have resiliently biasing properties which produce the bistable snap-action of the integral snap hinge.
In U.S. Pat. No. 5,642,824 a container closure is shown having a base for mounting to a container, and a lid connected to the base by a bistable, snap-action hinge structure. Similar to the integral snap hinge in U.S. Pat. No. 4,403,712, this hinge structure also has resiliently biasing properties producing a bistable, snap-action. However, unlike the integral snap hinge in U.S. Pat. No. 4,403,712, the hinge structure in U.S. Pat. No. 5,642,824 includes a film web having two distinct arcuate film hinges: an arcuate film hinge connecting the web to the base, and an opposing arcuate film hinge connecting the web to the lid. An abutment surface on the base controls the position of the hinge structure.
A resiliently biasing hinge structure similar to U.S. Pat. No. 5,642,824, is shown in U.S. Pat. No. 3,135,456 disclosing a flexible hinge device also having two arcuate film hinges. The hinge device conformably attaches surface-to-surface to a pair of coextensive cylindrical surfaces. only a web portion defined between the two arcuate film hinges remains unaffixed and freely movable. The two arcuate film hinges are hyperbolically opposed along a line of separation between the first and second cylindrical surfaces. And the two arcuate film hinges operate to produce a double hinge effect when the coextensive cylindrical surfaces are moved between open and closed positions relative to each other.
Although the types of container closures and hinge structures disclosed in U.S. Pat. Nos. 4,403,712, 5,642,824, and 3,135,456 have been useful in the personal care and household chemical markets, they do not adequately address the sanitary concerns existing in the pharmaceutical packaging industry. Sanitary dispensation is a paramount concern particularly for liquid pharmaceutical products packaged in liquid dispensing containers, such as oral hygiene products, cough and cold remedies, and topical medications, as well as products specifying liquid dosage amounts. Liquid pharmaceutical products are susceptible to dirt and bacteria contamination near and around the liquid discharge openings during a course of repeated use. Traditionally, nasal or dropper type caps have been designed with a separate tip inserted into the neck opening of a container, and a threadedly mating cap cover used to cover the separate tip. The nasal or dropper type caps typically have an extended spout tapered to a narrow tip which permits controlled dispensation in small quantities. However, because of its extended tip, the mating cap cover has been limited to non-captive covers mounting to and covering the cap.
The captive cover hinge structures disclosed in U.S. Pat. Nos. 4,403,712, 5,642,824, and 3,135,456, however, have inherent structural constraints which prevent the captive covers from clearing extended spouts when moved between open and closed positions over extended spouts.
In U.S. Pat. No. 4,403,712 the single, geometric main film hinge of the integral snap hinge functions as the sole pivot axis for moving the lid portion over the cap portion. When the hinge is operated, the pivot axis remains fixed and in a common plane with the top of the cap and the underside of the cover. This prevents the cover from clearing the extended spout of typical pharmaceutical dispensing caps; only spouts having relatively shallow heights can be cleared.
Likewise, in U.S. Pat. No. 5,642,824, the structural limitations of the biasing hinge structure prevent the lid from clearing the extended spout when moved to the closed position. In its preferred commercial embodiment, the proximity of the two arcuate film hinges causes the two hinges to approximate a single pivot axis when the hinge structure is operated. Similar to the snap hinge in U.S. Pat. No. 4,403,712, the single pivot fulcrum effectively remains fixed on the same elevational and vertical planes when the hinge is operated between the closed and open positions. Consequently, the lid is also not sufficiently elevated, laterally advanced, or otherwise advantageously repositioned to clear an extended spout of typical pharmaceutical dispensing caps.
Although the flexible hinge device in U.S. Pat. No. 3,135,456 utilizes two arcuate film hinges to create a double hinging effect, its orientation and attachment to the cover and container combination precludes any substantial elevation of the captive cover to clear an extended spout. In particular, the vertically hyperbolic orientation of the two arcuate film hinges at substantially the same vertical plane as the pair of coextensive cylindrical surfaces cancels the effect of any increase in distance between the apexes of the two arcuate film hinges. Any increase in spacing between the hinges to effect sufficient elevation and/or lateral movement of the captive cover to a superior approach position is undermined by the proportionally distanced location of the apex of each hinge from the respective contacting surface of the base or lid. Consequently, the cover maintains approximately the same shallow approach angle at the tip of an extended spout, regardless of variations in spacing between the hinge apexes.
Additionally, in U.S. Pat. No. 3,135,456, because only the web portion remains unaffixed to the pair of cylindrical surfaces, the resilient properties of the attached portions of the hinge device cannot be used to facilitate the snap-action at the two hinge axes. Further, the flexible hinge device can only be used with container and cover combinations having curved hinge attachment surfaces.